1. Field of the Invention
The present invention relates to a system of controlling a level of main feed-water in a steam generator of a nuclear power plant during a main feed-water control valve transfer to prevent an excessive level of the main feed-water in the steam generator.
2. Description of the Related Art
A nuclear power plant generally includes 100 or more systems respectively having individual functions. The systems are greatly classified into a nuclear steam supply system (NSSS) which is based on a nuclear reactor, a turbine/generator system which is supplied with steam to operate a generator so as to produce electricity, and other subordinate facilities. A pressurized water reactor (PWR), which is currently a main part of the nuclear power plant, includes a primary system which is based on a reactor, a secondary system which includes a steam generator, a turbine, an electric generator, and a condenser, an engineered safeguard system which is prepared for accidents, a power transmission and supply system, an instrumentation and control system, other subsidiary systems.
Hot water generated in a reactor circulates through a heat transfer pipe of a steam generator, which is connected to the reactor through a coolant pipe, to transfer heat to feed-water flowing into the steam generator through another pipe and then returns to the reactor. For the easy performance of this function of the steam generator, a level of the feed-water in the steam generator should be appropriately maintained. A feed-water control system of a nuclear power plant uniformly controls the level of the feed-water in the steam generator.